Sheets of resinous compositions have found widespread use as decorative and wear-resistant coverings for a wide variety of products. Possibly the largest use for such resinous sheet materials is in the resilient floor covering area wherein such resinous sheet materials are applied and adhered to floors or other like surfaces. In many instances, the resinous sheet materials are applied to or are formed on backing sheet materials of a fibrous, felted, matted, or nonwoven construction comprising cellulosic fibers, such as cotton or rayon, for example, in which may be incorporated relatively minor amounts, less than about 50% by weight, and preferably less than about 20% by weight of synthetic or man-made fibers of polyesters, polyamides, polyolefins, polyacrylics, modacrylics, etc. Such backing materials have very many purposes, the most common being that of increasing the strength, wear-life, and serviceability properties and characteristics of the resilient floor covering product.
Some of these resilient floor covering products are laid or installed in lengths of over 25 feet, or over 100 feet, or even more, in mobile homes, trailers, public buildings such as hospitals, libraries, museums, and the like and are usually adhered to the floor, or sub-flooring or other surface, by means of adhesives. Occasionally, when such a resilient covering is being adhered to a surface of great length by means of a water-based adhesive, it is noted that the resilient floor covering tends to "creep" or to "grow" immediately after being installed whereby swelling, buckling, or the appearance of bubbles or ridges takes place in the resilient floor covering. Such very undesirable tendency to grow is usually not noticed in installations of relatively short or moderate lengths. However, in installations of relatively great length, this undesirable growth in the resilient flooring product can become a very serious problem. Such undesirable growth is not limited to the length dimension or long direction of the resilient floor coverings. As a matter of fact, such undesirable growth is noted often in the width dimension or short direction which, although only 6 feet to 15 feet, exhibits relatively greater percentages of undesirable growth than the long or machine direction. It has also been observed that such undesirable tendency to grow is increased when the installation of the resilient floor covering takes place at relatively low percentages of relative humidity, say, below about 50%. In view of the fact that many installations of floorings frequently are carried out at relative humidities of from about 10% to about 50%, the undesirable growth properties must be carefully kept in mind and reduced or inhibited.